When the equipped creature becomes the target of a spell, the ability granted to it by Livewire Lash will trigger and go on the stack on top of it. It will resolve before the spell does.

1/1/2011

The equipped creature is the source of both the triggered ability and the resultant damage, not Livewire Lash. For example, you can target and deal damage to a creature with protection from artifacts (assuming the equipped creature isn’t an artifact itself, of course).